In conventional control devices to be used in vehicles, integration in which a control unit is unified with a motor has been proposed in order to reduce the size of, for example, an electric power steering device. In order to reduce the size of the entire device, it is also necessary to reduce the size of components to be used. For this reason, semiconductor modules have been used as an inverter for supplying and cutting off current to a motor. A plurality of switching elements are incorporated in each of the semiconductor modules. Mountability of the semiconductor modules is an important prerequisite to reduction of size and assemblability. Accordingly, a variety of aspects, such as heat dissipation, control amount output circuitry, and connectivity with motor windings, etc. must be taken into consideration in the semiconductor modules.
In a conventional electric power steering device, a motor case which houses a motor constituted by a rotor and a stator is used, and semiconductor modules are mounted thereon in a manner so as not to deviate in position. For this purpose, a special terminal extends from each semiconductor module. Further, a hole or groove for the special terminal to engage with is provided in the motor case, whereby the semiconductor module and the motor case are engaged with each other (see PTL 1, for example).